Apparatus for regulating pressure inside an autoclave

ABSTRACT

Pressure regulating apparatus in which the control maintaining the pressure inside an autoclave equal to the pressure inside containers holding the product being sterilized is connected to the output of the sensor means responsive to the pressure inside these sealed containers. The sensor means includes a probe carrying thereon a source of radioactive radiation and a detector of radioactive radiation. To effect the regulating operation, the probe is made to engage one of the containers being treated. Any displacement of the probe brings about a variation of the value of radioactive radiation being transmitted to the radiation detector, whereby the latter varies the output signal thereof, this signal controlling the operation of the control.

United States Patent Bezrodny et a1.

[111 3,804,591 [451 Apr. 16, 1974 APPARATUS FOR REGULATING PRESSURE INSIDE AN AUTOCLAVE Inventors: Konstantin Nikolaevich Bezrodny,

. ulitsa Arsenieva, 6a, kv. 8', Vladimir Nikolaevich Voit, ulitsa Pecherskaya, 8, kv. 33, both of Vladivostok, U.S.S.R.

Filed: Nov. 10, 1971 App1.No.: 197,294

[30] Foreign Application Priority Data Aug. 29, 19 68 U.S.S.Rl 1266706 Aug. 29, 1969 U.S.S.R 1348442 References Cited UNITED STATES PATENTS 1/1959 Poitras 21/94 X 3/1962 Stoffer et a1. 202/160 5/1970 Fritzberg et a1. 21/93 X 3,531,300 9/1970 Greenberg et a]. 99/214 OTHER PUBLICATIONS Industrial Isotope Techniques by, Lars. G. Erwall et a1., John Wiley & Sons Inc., New York (1964), pp. 117-119.

Primary Examiner.lose'ph Scovronek Assistant ExaminerTim Hagan Attorney, Agent, or Firm-Holman & Stern 5 7] ABSTRACT Pressure regulating apparatus in which the control maintaining the pressure inside an autoclave equal to the pressure inside containers holding the product being sterilized is connected to the output of the sensor means responsive to the pressure inside these sealed containers. The sensor means includes a probe carrying thereon a source of radioactive radiation and a detector of radioactive radiation. To effect the regulating operation, the probe is made to engage one of the containers being treated. Any displacement of the probe brings about a variation of the value of radioactive radiation being transmitted to the radiation detector, whereby the latter varies the output signal thereof, this signal controlling the operation of the control.

2 Claims, 1 Drawing Figure APPARATUS FOR REGULATING PRESSURE INSIDE AN AUTOCLAVE BACKGROUND OF THE INVENTION The invention relates to apparatus for thermal treatment of products, and, more particularly, it relates to apparatusforregulating pressure inside an autoclave in the course of the sterilization of products received within sealedcontainers, or cans. The invention can be employed for treatment of foodstuffs, particularly when the latter are received within containers with thin walls, e.g., with wall thickness below 0.22 mm.

A known apparatus for regulating automatically the pressure inside an autoclave comprises a sensor means responsive to the pressure inside a container holding the product, anda control of the supply of compressed air into the autoclave. The pressure-responsive sensor means in this known apparatus includes a movable stem positioned to engage a sample sealed container and a hydraulic element in the form of, for instance, a sealed tube filled with a liquid, one end of this tube, serving as the input, being closed with-a resilient diaphragm, the other-end of this tube, i.e., the output one being associated with the abovementioned control. When an autoclave incorporates the abovedescribed sensor means, a special cavity is made inthe wall of the autoclave to accommodate the sample sealed container, and the stem is made to extend through the wall of'this cavity to the exterior of the autoclave, with the help of a suitable seal. I I

A disadvantagebf this known structure is the fact that the bulk of thesealed containers being treated and I the sample one are subjected to different physical conditions, which substantially reduces the accuracy of maintaining equality of the pressure inside and outside the sealed containers being treated, e.g., sterilized.

The external and of the stem being subjected to atmospheric pressure, while the internal end thereof is subjected to the gaugepressu'reinside the autoclave, there arises anecessity of providing a return spring. However, the presence of the return spring and of the seal increasesthe inertia of the operation of the appara tus. I

, SUMMARY or THE INVENTION I It is an objector thegpresent invention to improve the accuracy of maintaining equality of the pressure inside and outside sealed containers being sterilized in an autoclave, as well as to reduce the inertia of the operation of the pressureregulating apparatus.

This and other objects are attained in an apparatus for regulating pressure inside an autoclave in the course of an operation of sterilization of products receivedwithin sealed containers, comprising a sensor means responsive to the pressure inside one of said,

sealed containers, having the output thereof connected I toclave, adapted to respond to the flow of radioactive radiation from said source and to vary the output signal thereof in response to a displacement of said probe.

With the apparatus constructed in accordance with the invention, the sensor means thereof provides for effecting pressure regulation byempl'oying any one of the containers being treated as the sample one, all the containers in the autoclave being subjected to the same physical condition, whereby it becomes possible to imchannel perpendicular to a groovemade therein, said I groove serving as a guideway for said probe, said channel being intended for emitting the radioactive radiation from said, casing, said radiation detector being mounted exteriorly of said autoclave, in opposition to said other groove. I

BRIEF DESCRIPTION oE'rIIE DRA I G regulating apparatus in accordance with the invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT v I In the drawing, the housing 1 of an autoclave has rigidly mounted onthe internal wall thereof a lead casing 2 in the walls of which a perpendicular channel 3 and perpendicular groove 4 are cut. The groove 4 receives therein a movable probe 5 of which' the upper portion carries a source 6 of radioactive radiation. In the courseofa regulating operation the bottom end portion of the probe Sis made toengage a container "7 supported by asupport platform 8 mountedonthe wall of the housing 1. The autoclave being intended for steril ization of containers of different'height, the support platform should be made movable in respect of the bottom, face of the casing 2. Mounted exteriorly of the housing 1, in opposition to the channel 3 is a detector 9 of radioactive radiation. The movable probe 5, the radioactive source 6 carried on the probe 5 interiorly of the casing 2, and the detector 9 make up together a system responsive to the pressure inside the container 7 the source 6 the container 2 and detector 9 forming a means transmitting a signal indicative of the amount of displacement of the probe 5 which corresponds to pressure change. Connected to the output of the detector 9 is an electronic relay 10 operatively associated with the compressed air supply control 11 and with the steam and air exhaust control 12. t

The two abovementioned controls canbe in the form of any suitable known control valves.

Temperature inside the autoclave can be controlled by a program-operated temperature regulator 13 in cluding a commonly known balanced electronic bridge circuit of which one of the arms includes a temperature-responsive resistor 14 mounted interiorly of the housing 1 of the autoclave. The output of the programoperated temperature regulator is connected to the steam supply control 15, to the water supply control 16 and to the upper exhaust control 17.

Mounted at the bottom portion of the herein disclosed autoclave is a water drain valve 18. The autoclave is provided interiorly thereof with a floor 19 adapted to support a trolley 20 with containers 7 that are to be treated.

The herein disclosed apparatus operates, as follows:

Prior to'a sterilization operation, a trolley 20 with containers 7 is positioned on the floor 19 of the autoclave, and one of the containers is put onto the support panel 8. The probe 5 is made to engage physically the lid of the last-mentioned container 7, with the probe 5 being so positioned that the radioactive source 6 carried thereby should be at the level of the lower edge of the channel 3, so that the radiation from the source 6. should not reach the detector 9.

Then the housing 1 of the autoclave is closed with a lid (not shown in the drawing), and the programoperated temperature control 13, the temperature pickup 14 and the relay are energized. Now the control valves 12, and 17 are open, and the control valves 11 and 16 are closed. The drain valve 18 is also closed. The steam is supplied through the control valve 15 into the housing 1 where it heats up the containers with the foodstuff thereinside, whereafter the steam finds its way from the autoclave through the control valves 17 and 12. The containers 7 are heated up to a preset sterilization temperature, whereafter the control valve 17 is closed, while the control valve 15 is alternately opened and closed to maintain the desired sterilization temperature within the housing 1.

in the course of the sterilization operation the pressure inside the containers 7 rises until the gauge pressure thereinside drives the sealed lid of the container 7 (the one supported on the platform 8) upwardly, whereby the probe 5 with the radioactive source 6 carried thereby is driven upwardly in the groove 4 of the casing 2, and the source 6 becomes positioned at the channel 3 The detector 9, in response to the increased radioactive radiation, sends a control signal through the relay 10 to the control valve 11. With the control valve 11 open, compressed air is supplied therethrough into the housing 1 until the pressure within the housing 1 equals the pressure within the container 7. When this is achieved, the probe 5 with the radioactive source 6 returns to its initial position, whereby the corresponding output signal of the relay 10 brings about the opening of the control valve 12 and closing of the control valve 11. However, in this case water is not drained from the housing 1, because the control valve 17 connected in series with the control valve 12 remains closed.

In this way there is carried out the thermal sterilization stage of the canned foodstuff, throughout which the temperature within the housing 1 is maintained at a preset level, and the pressure thereinside is maintained equal to the pressure within the containers.

When the predetermined time interval elapses, the program-operated temperature control 13 closes the control valve 15 and opens the control valves 17 and 16. Should the pressure inside the housing 1 fall below the pressure within the container 7 on the platform 8, the lid of the container drives upwardly the probe 5, making the latter rise together with the radioactive source 6 along the groove 4. As a result, the beam of radioactive radiation intercepted by the detector 9 is increased, and the output signal of the latter makes the relay l0 send a control command to open the control valve 11 and to close the control valve 12 until the pressure inside the housing 1 equals again the pressure inside the sealed containers 7.

The abovedescribed alternating opening and closing of the control valves 11 and 12 would be continued until the temperature and the pressure within the autoclave are brought down to the desired values.

The herein disclosed apparatus makes it possible to cut down considerably the time of cooling down of sealed containers inside an autoclave and also to positively prevent any irreversible deformation of sealed containers filled with a product to be sterilized.

What we claim is:

1. In an apparatus for regulating pressure inside an autoclave supplied with a working agent during sterilization of products sealed within a plurality of pressurized containers, comprising control means for controlling the supply of the working agent to maintain the pressure in the autoclave equal to the pressure inside said containers, a pressure sensor means including a movable probe positioned inside said autoclave, one end of said probe being in physical contact with one of said containers located on an individual platform in said autoclave, a signal transmission means for transmitting a signal indicative of the extent of movement of said probe in accordance with pressure changes in said control means, the improvement wherein said signal transmission means includes a source of radioactive radiation secured at the other end of said probe, a rigidly fixed casing means which is non-transparent .to radioactive radiation and is adapted to movably receive that end of the probe carrying the source of radioactive radiation, said casing means being provided with a channel to permit the emission of radioactive radiation, and detector means for detecting the radioactive radiation and mounted exteriorly of said autoclave opposite to said channel and operatively connected to said control means so as to operate said control means in response to changes in the emission of radioactive radiation detected by said detector means.

2. An apparatus as claimed in claim 1, wherein said radioactive radiation source carried by said probe is received within said casing means which is fixedly mounted interiorly of said autoclave, said casing means having in addition to said channel a groove made therein, and said groove serving as a guideway for said probe. 

1. In an apparatus for regulating pressure inside an autoclave supplied with a working agent during sterilization of products sealed within a plurality of pressurized containers, comprising control means for controlling the supply of the working agent to maintain the pressure in the autoclave equal to the pressure inside said containers, a pressure sensor means including a movable probe positioned inside said autoclave, one end of said probe being in physical contact with one of said containers located on an individual platform in said autoclave, a signal transmission means for transmitting a signal indicative of the extent of movement of said probe in accordance with pressure changes in said control means, the improvement wherein said signal transmission means includes a source of radioactive radiation secured at the other end of said probe, a rigidly fixed casing means which is non-transparent to radioactive radiation and is adapted to movably receive that end of the probe carrying the source of radioactive radiation, said casing means being provided with a channel to permit the emission of radioactive radiation, and detector means for detecting the radioactive radiation and mounted exteriorly of said autoclave opposite to said channel and operatively connected to said control means so as to operate said control means in response to changes in the emission of radioactive radiation detected by said detector means.
 2. An apparatus as claimed in claim 1, wherein said radioactive radiation source carried by said probe is received within said casing means which is fixedly mounted interiorly of said autoclave, said casing means having in addition to said channel a groove made therein, and said groove serving as a guideway for said probe. 